I was sifting through some papers and found a SuDoku I had tried previously, but couldn't solve... So I erased everything and started over hoping time had made me skilled enough to solve it Apparently not.
So I consult people that are better than me
It currently looks like so:

000 000 089
790 002 300
010 093 270

854 136 792
000 905 000
901 280 503

009 320 050
005 600 024
280 000 030

The hint says that r9 c3 is a 7, I don't understand why at all. Could someone please help me?